| OCR Text |
Show 54 5.5 Tests J\llm P asurf~ ll! P nt s in th is S f~ct iou arP elapsed timf~s . Mea.suremP.nts r<~po r tecl here a re t he elapsed times to "create" , "load" , and "update" an obj ect graph. These tPsts wt>rt' run in both "local" and "rctlWtt>" settings three times and the ave ragP ti me nH~ a.s ur P nwnt s are reported . From a performance poin t of view , create involves creating OIDs, all ocat ing space Cor tll<' obj ect s, and creat ing meta-data, sucb as, mapping tables , indi ces, etc. For creation, a ll locks that a rP obtained a.re wri te locks . In systems that (-~ mploy logging for recovPry, t b(~ after-image of the obj ect is saved. Load requires access ing and locks. l'pd ate itJvolv(-'S C1CC( 'ss itl !2, at1d vvriti11g t lw obj (-'C t s. 'This leads to acq 11iring (':\ ( llt sivl' locks on a ll objects beiug updated . For recovery in sys tems employing loggiu g, both tbe before-image and the after-image is recorded. In Llw local set t ing, hoth t he server and t he cli ent are executing on tbe same mach in e. In the remote case, the st-TV(~ r and t be cliPnt are on S (~par at e m;:tc bin Ps cl.llcl a.ny communication between tlwrn ha.s to go over the network. Tlw f'ollowi 11g table shows Lbe amOJJnL of space that was required to storP an object grap h. Th is object graph is an Alpba_l model represe nting an espresso. It has :29!J objects with avP ragr object size of 1:39.5 bytes . All sizes in the table are in hyLcs. POS Initial [)13 Sizt· Object. Crap l1 Size l\lpba.l 0 ·fUt\9 01 >St>l' \i('r 6:H1 I 72!) ()!1 I ·~ S~/1 !)7:)41! 7:37 :20 1\,stgres 4C)l f)24 90:304 5 .5. 1 C ornman !\!lost of t lwsP tests a.re m icro-t(-'sts, meaning t hat each one meas ures a pa rti cular feature of the POSs. T ime measurements for Postgres are too high fo r certain |
